Apparatus for anchoring the pilot member in a pilot bore



June 4, 1968 j c, LAWRENCE ETAL 3,386,520

APPARATUS FOR ANCHORING THE PILOT MEMBER IN A PILOT BORE Filed April 1,1966 v 5 Sheets-Sheet l INVENTORS JAMES c. LAWRENCE By WILL/AM H.HAMILTON ATTORNEYS Jun 4. 9 J. c. LAWRENCE ETAL 3,386,520

APPARATUS FOR ANCHORING THE PILOT MEMBER IN A PILOT BORE 5 Sheets-Sheet2 Filed April 1, 1966 Oh mm v INVENTORS I 1 JAMES C. LAWRENCE BYW/LL/AMH. HAMILTON MWWZW w 09 AT OR/VEYS June 4, 1968 J. c. LAWRENCEETAL 3,386,520

APPARATUS FOR ANCHORING THE PILOT MEMBER IN A PILOT BORE Filed April 1,1966 3 Sheets-Sheet a 53 INVENTORS JAMES C. LAWRENCE WILL/AM H. HAMILTONA T TORNE Y8 United States Patent 3,386,520 APPARATUS FOR ANCHORING THEPILOT MEMBER IN A PILOT BORE James Clifton Lawrence and William HauthHamilton,

Seattle, Wash, assignors to Alkirk, Inc., Seattle, Washington, acorporation of Delaware Filed Apr. 1, 1966, Ser. No. 539,354 11 Claims.(Cl. 175-230) ABSTRACT OF THE DISCLOSURE This invention relates to ananchor assembly and particularly to an anchor assembly of specialconstruction for fixing the pilot tube of a rock or earth boring machineWithin a pilot bore with sufficient holding action to withstand thereaction forces exerted on the anchor as the machine is pulled forwardlyto cut a main bore in the material in which the pilot bore is formed.

The invention refers in general to the type of earth or rock machinedisclosed in Reissue Patent No. 24,965. Many different types of anchorunits have been proposed for the various forms of this machine, andwhere the material being cut is relatively soft such as coal expansibleresilient means has been found adequate. However, as the hardness of thematerial to be cut increases the demands on the anchor correspondinglyincrease, and in cutting into rock it has been found that hithertoavailable anchors are entirely inadequate. It was not until the presentinvention was made that an anchor assembly for such a machine capable ofwithstanding the forces exerted on it during rock tunnelling becameavailable. It has been found that the steering or directional changes ofthe bore is an essential function of a modern and versatile boringmachine. Hitherto types of pilot anchors have not been suitablyconstructed to allow for this all important motion.

It is therefore the major object of the invention to provide a novelpilot tube anchor assembly for a rock and like boring machine.

A further and basic object of the invention is to provide a pilot anchorso constructed as to allow the pilot anchor to swing about its grippingshoes as the boring machines directional axis is changed.

Another object of the invention is to provide a novel pilot anchorassembly wherein pilot bore gripping slips or shoes are wedged forciblyoutwardly in a novel manner.

It is a further object of the invention to provide a pilot tube anchorassembly of novel construction wherein a series of circumferentiallyarranged bore gripping elements are displaced outwardly by fiuidpressure.

A further object of the invention is to provide a novel pilot tubeanchoring arrangement wherein a relatively fixed piston is mounted onthe tube surrounded by an axially slidable cylinder that moves in theforward direction along the pilot tube to outwardly displace boregripping elements, and particularly the novel mounting of these boregripping elements and their motion transmitting connections with thecylinder.

It is a further object of the invention to provide a novel pilot tubeanchor assembly having correlated but 3,386,520- Patented June 4, 1968distinct bore gripping means and bore sealing means located forwardlytherefrom, both being actuated in unison by the same fluid pressuremeans.

In general, the foregoing and other objects are carried out by providingin combination with a rock boring machine having a pilot member adaptedto project forwardly from the machine into a pilot bore, an expansibleanchor assembly carried by said pilot member for fixing said pilotmember within said bore comprising: an annular support mounted on saidpilot member having a plurality of circumferentially spacedlongitudinally extending forwardly upwardly inclined guideways, borewall engaging elements slidably mounted in said guideways, an actuatormember axially slidably mounted on said pilot member, means fordisplacing said actuator member axially along said pilot member wherebyforward axial movement of said actuator member on said pilot memberresults in outward displacement of said bore wall engaging elementsrelative to said annular support, the surface of said elements beingshaped in a direction parallel to the longitudinal axis of the pilotmember to facilitate rocking of said pilot member about said anchorassembly.

Further objects of the invention will appear as the description proceedsin connection with the appended claims and the annexed drawings wherein:

FIGURE 1 is a fragmentary view partly in section showing the front endof an earth or hard rock boring machine according to a preferredembodiment of the invention;

FIGURE 2 is an enlarged elevation partially broken away and in sectionshowing the pilot anchor assembly details;

FIGURE 3 is an end view of the anchor assembly;

FIGURE 4 is a partially sectioned end view of the anchor assembly,mainly along line 44 of FIGURE 2; and

FIGURE 5 is an elevation partially broken away and in section showingthe angular capabilities of the pilot anchor.

Referring to FIGURE 1, the machine comprises a frame 9 having bearingssuch as at 10 for rotatably mounting a main cutter head 11. Cutter 11 issuitably power driven to rotate about the axis AA and it carries on itsfront surface a series of roller cutter elements 12 that are adapted toengage and cut the main tunnel or bore face 13.

A hollow cylindrical pilot tube 14 coaxial with axis AA projects freelythrough a central aperture in cutter head 11, and tube 14 isnon-rotatable but is axially slidable with respect to head 11.

A pilot cutter shaft 15 projects coaxially freely through the bore oftube 14 and carries at its front end a pilot cutter head 16.

As illustrated in FIGURE 1, the pilot cutter extends into a pilot bore17 that it forms ahead of the main cutter, and the pilot tube carries ananchor assembly 18 that anchors the pilot tube 14 rigidly within thepilot bore 17, the diameter of pilot bore 17 being larger than therelaxed anchor 18.

The machine comprises a mobile frame on which main cutter head 11 issuitably mounted and rotatably driven. The pilot tube is axiallyslidably mounted on the frame independently of cutter head rotation, asby a suitable hydraulic cylinder and piston arrangement, and the pilotcutter shaft 15 is rotatably mounted and driven by suitable means on theframe. Preferably the pilot cutter moves axially with the pilot tubeduring machine operation. In operation, the pilot cutter 16 forms aheadof the machine a relatively small pilot bore such as that at 17, as itrotates and advances to the left of material face 13. Then, orconcurrently, pilot tube 14 is thrust into pilot bore 17, and the anchorassembly 18 is expanded to grip the wall of bore 17. Now the main cutter11 is rotated and, reacting from the anchor at 18, is pulled bodilytoward and into face 13 to cut the main bore during entry.

The foregoing is generally of the same construction and mode ofoperation as disclosed in U.S. Reissue Patent No. 24,965 and Ser. No.416,075 filed Dec. 4, 1964, and the essential improvement to be morespecifically disclosed hereinafter and claimed is the novel anchorassembly at 18, shown in enlarged detail in FIGURES 2-4.

FIGURES 2-4 show anchor 18 on the end of pilot tube 14. Anchor 18comprises an annular piston assembly 21 that is axially fixed on tube 14by snap ring and groove assemblies at 22 and 23 and is surrounded by thebore 24 of a cylinder 25. The rear end of cylinder 25 is closed by anannular bushing 26 that slidably engages the periphery of cylindricaltube 14 at 27 and is retained on the cylinder by annular nut 28 threadedinto the cylinder at 29. A retainer ring 31 secured to bushing 26 as byscrews 32 holds a compressible seal ring 33 in peripheral engagement wthpilot tube 14.

The outer periphery of piston 21 comprises an annular bushing 34 havingresilient O-ring seals 35 with cylinder bore 24 and removably mounted onthe piston as by screws 36, and a static O-ring 37 is provided at theinternal bore of piston 21. Suitable peripheral O-ring seals 38 and 39are also provided between bushing 26 and the concentric surfaces of thecylinder bore 24 and pilot tube 14.

Hydraulic fluid may enter the cylinder through either of ports 41 or 88for operation as will appear.

Forwardly of piston 21 cylinder 25 is closed by a bushing 43 fixed tocylinder 25 and slidably surrounding tube 14 and having O-ring seals at44 and 45.

An actuator ring 46 is secured to cylinder 25, as by bolts 47, and therear end of ring 46 is piloted at 48 into the cylinder end for radialrestraint.

Forwardly of ring 46 is an annular support member 51 having inclinedflat longitudinally extending guideway surfaces 52 lying tangential to acone of revolution about the axis of the pilot tube. As shown in FIGURE4, these surfaces 52 are equally circumferentially spaced about the axisof the anchor, and they are radially equidistant from that axis. Anannular nut 53 is secured upon the end of tube 14 as by the threadedconnection 54. Member 51 is interiorly slidably supported by a bushing55 on tube 14 and a bushing 56 on nut 53, there being an axial clearancebetween the cone and nut at 57 for a purpose to appear.

Nut 53 and the adjacent end of member 51 are formed to define betweenthem an annular groove 58 which contains a packing ring assembly 59 ofcompressible resilient material such as synthetic rubber.

A plurality of bore gripping elements in the form of shoes or slipmembers 61 have fiat inner surfaces 62 slidably engaged with surfaces 52and are circumferentially distributed about member 51 at the bottoms oflongitudinal surface channels 63 that are cut in equally spaced relationaround member 51 to provide surfaces 52. As shown in FIGURE 4 theopposite sides of channels 63 are inclined to diverge outwardly fromsurfaces 52 and the oposite sides of slip members 61 are correspondinglyinclined, to provide for longitudinal slide guiding and radial retentionof slip members 61 on member 51. Each slip member bears on its outersurface a number of pointed teeth or projections 64 for gripping thematerial bore as will appear. It will be particularly observed that theouter tooth bearing surfaces of slip members 61 are arcuately convexboth in the longitudinal direction (FIGURE 2) and transversely (FIGURES2 and 4), to provide rocking surfaces facilitating the steeringoperation of the machine disclosed in said Ser. No. 416,075 in thatthese surfaces facilitate shift of the ma- 4- chine about the anchor asa pivot during such steering, as best shown in FIGURE 5.

As shovm in FIGURE 2, each slip member 61 is arcuately formed at itsrear end 65 to fit with a corresponding arcuate surface 66 on actuatorring 46, and all of the slip members 61 are connected to actuator ring46 by similar dumbell-shaped rigid motion transmitting members 67 thathave enlarged arcuate ends 68 and 69 disposed in similarly shapedsockets 71 and 72 in the slips and actuator ring respectively.

Sockets 71 and 72 have their walls similarly inclined, preferably at thesame angle relative to the axis of the pilot bore, and radial outwarddisplacement of members 67 from their sockets is prevented by a seriesof retainer pins 73 extending between grooves 74 and 75 in the slips andthe actuator ring.

In operation of anchor assembly 18, with the pilot tube disposed inpilot bore 17, hydraulic fluid from passage 40 in the pilot tube isintroduced at port 41 into the cylinder at the forward side ofrelatively fixed piston 21, whereby the entire cylinder assembly 25 isslidably displaced forwardly or to the left in FIGURES 1 and 2. Actuatorring 46, which is fixed to cylinder 25, transmits force through theconnecting members 67 to slips 61 all of which are simultaneouslydisplaced to the left in FIGURE 2.

Because of the sliding inclined wall socket connection at 68 slips 61are permitted to become simultaneously displaced radially outwardly asthey travel longitudinally forwardly along surfaces 52 so thatprojections 64 are forced into the wall of the surrounding pilot bore inthe material to be cut. As slips 61 proceed up the inclines 52 on member51, the resistance encountered progressively increases as the carbidetips 64 penetrate deeper into the surface of the pilot bore. This forceis transmitted to the front cone assembly and during the initial stagesof penetration of projections 64 into the bore 17 the force issuificient to axially move member 51 forwardly, to the left in FIGURE 2,sufiiciently to compress the resilient packer ring assembly 59 while thecarbide tips of projections 64 are initially slipping at the boresurface, until such time as the clearance 57 between member 51 and thenut 53 is used up and member 51 abuts nut 53. This axial compression ofpacking ring 59 causes it to expand radially outwardly into a fluidtight peripheral sealing fit with the pilot bore. As can be seen inFIGURE 2 the relative travel between member 51 and the nut 53 can beregulated by using different lengths of bushings 56. This seal preventswater and the like from leaking through the pilot bore to decrease theholding action of the anchor and otherwise interfere with operation ofthe machine. As this occurs, slips 61 proceed further along the inclines52 of the cone member 51 and outwardly until carbide tips 64 becomingembedded with their radial penetration force being equal to the lateralcomponent of the actuation force. This sets the anchor 18 so that thepilot tube 14 is now fixed within bore 17 and becomes rigid with thematerial being cut.

When anchor 18 is thus expanded and set, the axial force necessary forcutting originating in the machine is transmitted solidly through thepilot tube 14, the body nut 53 and support member 51. The lateralcomponent of this axial force increases the effective frictioncoefiicient between the slips and the pilot bore at the same rate as theaxial force is increasing by tending to displace the slips outwardly sothat after setting the anchor 18 becomes self energizing.

In order to introduce lubricant between the relatively sliding surfaces52 and 62, an annular recess 81 is provided around the interior ofmember 51 and recess 81 is connected by radial passages 82 to eachsurface 52. As shown in FIGURE 4, member 51 is provided with a radialpassage 83 leading from recess 81 to a grease aaaaszo fitting 84recessed into a small threaded bore 85 normally closed by a removableplug 86.

To release anchor 18, hydraulic fluid is pumped along pilot tube passage87 into the cylinder at a port 88 at the rear (right hand) of fixedpiston 21, this moving the cylinder assembly and actuator ring 45rearwardly toward the position shown in FIGURE 2. This force istransmitted to slips 61 through the action of connecting members 67pulling the slips down the inclined ways 52, and the resilientpacker-ring 59 contracts radially as it expands axially simultaneouslywith slip movement.

As shown in FIGURE 2 the seal annulus '59 consists of an inner resilientannulus 91 and two side by side outer annuli 92 and 93 the reduced outerends of which project through the restricted mouth 94 of an annularaxial space 95 between the nut 53 and memberSl. This arrangement hasbeen found to provide adequate expansion for sealing and when worn onlythe outer rings 92 and 93 need be replaced.

FIGURE 5 shows the angular displacement capabilities of the anchorassembly. The machine is shown as disposed in pilot bore 17 on the pilotbore axis indicated at AA. As disclosed in Ser. No. 416,075 the axis ofthe main cutting head 11 may be angularly incrementally shifted bydisplacement of the entire machine to change the direction of cutting ofthe main bore, and this incremental shift is indicated at angle awhereby the cutting head axis is shifted from axis AA to axis BB inFIGURE 5. This shift is facilitated greatly by the arcuate shoes 61which permit the necessary tilt in the tube 14 while retaining the tubeaxially anchored within pilot bore 17.

The foregoing anchor may be used in any machine of this type wherein aprojecting pilot tube is to be fixed within the pilot bore. Where thepilot bore may be cut by a separate drill or the like, tube 14 need notbe hollow. In a rock tunneling machine having a main cutter about 12feet in diameter for cutting a bore of that size in rock we have foundthat an anchor of the invention that expands between about 24 inches inoutside diameter when relaxed and about 26 inches in diameter whenexpanded to grip the pilot bore wall will withstand a thrust force ofabout 1,500,000 pounds exerted to pull the main cutter into the rockface to be cut.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In combination with a rock boring machine having a pilot memberadapted to project forwardly from the machine into a pilot bore anexpansible anchor assembly carried by said pilot member for fixing saidpilot member within said bore comprising: an annular support mounted onsaid pilot member having a plurality of circumferentially spacedlongitudinally extending forwardly upwardly inclined guideways, borewall engaging elements slidably mounted in said guideways, an actuatormember axially slidably mounted on said pilot member, means fordisplacing said actuator member axially along said pilot member wherebyforward axial movement of said actuator member on said pilot memberresults in outward displacement of said bore wall engaging elementsrelative to said annular support, the surface of said elements beingshaped in a direction parallel to the longitudinal axis of the pilotmember to facilitate rocking of said pilot member about said anchorassembly.

2. In the combination defined in claim 1, an annulus in said anchorassembly disposed forwardly of said elements and operably connected tobe expanded into sealing relation with said bore by said forward axialmovement of said actuator member.

3. In the combination defined in claim 1, said pilot member being ahollow tube, and a rotatable pilot cutter extending through said tube toout said pilot bore.

4. In the combination defined in claim 1, said anchor assemblycomprising a piston axially fixed on said pilot member and a fluidpressure cylinder surrounding said piston axially slidably mounted onsaid pilot member, said actuator member being rigid with said cylinder.

5. In the combination defined in claim 1, said support member beingmounted on said pilot member for limited axial sliding movement relativeto said pilot member and further comprising an annular end member fixedon said pilot member, a resilient annulus axially mounted between saidend member and support members, said support member being forwardlydisplaced during initial forward movement if said actuator member is tocompress said resilient annulus and expand it radially into sealingrelation with the wall of said bore.

6. In the combination defined in claim 1, means for lubricating saidguideways comprising an annular passage between said support member andpilot member connected to a radial lubricant introduction passage in thesupport member, and radial branch passages between said annular passageand said guideways.

7. In the combination of claim 1, the shape of the surface of saidelements in the direction parallel to the longitudinal axis of saidpilot member being arcuate.

8. In the combination of claim 1, said anchor assembly furthercomprising individual motion transmitting members extendinglongitudinally between said actuator member and each of said boreengaging elements, said elements and said motion transmitting membershaving abutting end surfaces in slidable engagement so that said boreengaging elements can move outwardly relative to said motiontransmitting members.

9. In the combination defined in claim 8, said relatively slidable endsurfaces between each motion transmitting member and its associated boreengaging element extending angularly from said guideways.

10. In the combination defined in claim 8, said motion transmittingmembers having enlarged ends disposed in sockets formed in said actuatormember and said elements respectively.

11. In the combination defined in claim 10, said motion transmittingelements being of essentially dumbell shape with said enlarged endsbeing rounded.

References Cited UNITED STATES PATENTS 1,471,808 10/1923 Russ 227 X1,983,287 12/1934 Grinnell et al 175-99 X 3,180,419 4/1965 Cochran et al166l20 FOREIGN PATENTS 124,898 1959 'U.S.S.R.

ERNEST R. PUR'SER, Primary Examiner.

